Display device

ABSTRACT

A display device is provided, including a display panel; a light-emitting element disposed under the display panel; an optical functional film disposed between the display panel and the light-emitting element. The optical functional film is capable of transmitting at least part of the light emitted from the light-emitting element. A diffuser film is disposed between the display panel and the light-emitting element. The haze of the diffuser film is greater than 85%, and the thickness of the diffuser film ranges from 0.1 mm to 0.3 mm.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of provisional application of ChinaPatent Application No. 201910517111.2 filed on Jun. 14, 2019, theentirety of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to a display device, specifically to adisplay device with a back light source.

Description of the Related Art

Display devices have become indispensable for current electronic devicesto deliver information to users, and for users to conduct intuitiveinteractions with their electronic devices.

However, as technology develops, consumers are demanding more fromdisplay devices. For example, they are expecting the display devices tohave a broader color region, color that is more vivid, and higherdynamic contrast, so the image can be more detailed. Thus, currentdisplay devices still have need for improvement.

SUMMARY

The present disclosure provides a display device, comprising a displaypanel; a light-emitting element disposed under the display panel; anoptical functional film disposed between the display panel and thelight-emitting element, wherein the optical functional film is capableof transmitting at least part of the light emitted from thelight-emitting element; and a diffuser film disposed between the displaypanel and the light-emitting element. The haze of the diffuser film isgreater than 85%, and the thickness of the diffuser film ranges from 0.1mm to 0.3 mm.

To more clearly understand the present disclosure as described and otherpurposes, features and advantages, some embodiments of the disclosurewill be described in detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is illustrates the cause of low dynamic contrast of a displayimage of a display device.

FIG. 2 illustrates a cross-sectional view of a display device, withschematic explanation of the principles, according to some embodimentsof the present disclosure.

FIGS. 3 and 4 illustrate cross-sectional views of display devices,according to some embodiments of the present disclosure.

FIGS. 5 and 6 illustrate cross-sectional views of display devices,according to other embodiments of the present disclosure.

FIG. 7 illustrates a cross-sectional view of a display device, accordingto some embodiments of the present disclosure.

FIG. 8 illustrates cross-sectional views of individual micro-structures,according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The following will explain in detail a display device provided by thepresent disclosure. It should be understood that the followingdisclosure provides many different embodiments or examples, forimplementing different features of the present disclosure. The specificfeatures and their positions are described as followed, to simplify thespecification of the embodiment of the disclosure. These are, of course,merely examples and are not intended to be limiting. In addition, thedisclosure may repeat reference numerals and/or letters in variousembodiments, to more clearly describe the present disclosure. However,this repetition is for the purpose of simplicity and clarity, and doesnot in itself dictate a relationship between the various embodimentsdiscussed.

It should be understood that elements or devices in the figures mayexist in various forms known by those skilled in the art. Furthermore,spatially relative terms, such as “underlying,” “below,” “lower,”“overlying,” “upper”, “upper”, and the like, may be used herein for easeof description to describe one element or feature's relationship toanother element(s) or feature(s) as illustrated in the figures. Itshould be understood that if the apparatus were otherwise oriented(rotated 90 degrees or at other orientations), then the spatiallyrelative descriptors used herein may likewise be interpretedaccordingly, for example, the “lower” side of the device will become the“higher” side after orientation. The present disclosure may becomprehended with accompanying figures, in which the figures are alsoconsidered as part of the present disclosure. It should be understoodthat various features are not drawn to scale. In fact, the dimensions ofthe various features may be arbitrarily increased or reduced for clarityof discussion.

The terms “about”, “approximately”, “substantially”, and “essentially”used herein generally refer to the value of an error or a range within5%, preferably within 3%, and more preferably within 1%, or 2%, orwithin 1%, or 0.5%. The given values are approximate values. If there isno specific description on “about”, “approximately”, “substantially”, or“essentially”, the values mentioned are still to be regarded as an erroror range expressed as “about”, “approximate”, “substantially”, or“essentially”.

In some embodiments of the present disclosure, terms that describe ajoining or connecting action, such as “connect”, “interconnect”, or thelike, unless otherwise defined, may include embodiments in which twofeatures are formed in direct contact, and they may also includeembodiments in which additional features may be formed between the twofeatures. Furthermore, it should be understood that related terms, suchas “over . . . ” or the like, described in the present disclosure mayinclude embodiments being in direct contact with the subject to becovered, and they may also include embodiments in which additionalfeatures on the subject before the subject is being covered, so thesubject and the additional features may partially overlap when viewedfrom above, so the coverage is not in direct contact.

Since non-self-luminous display devices have display elements (such asliquid-crystal display panel) that does not illuminate itself, and thus,displaying images requires additional back light source to provide thenecessary lighting during display. For example, light-emitting diode maybe applied as the light-emitting element of the display device lightsource, and the structure applied can be distinguished into direct backlight source directly arranged behind the display panel, and edge-litback light source arranged around the panel's perimeter. When applyingthe structure of direct back light source, besides the advantages ofhigh light output efficiency, no need of light guide plate, and fewerspare parts, local dimming on smaller area may also be performed.

The so-called local dimming changes the brightness of the display regionlocally by controlling the brightness of individual light source basedon the image data of the display device shown. For example, dynamiccontrast of the image can be increased by having low brightness (even nobrightness) at image dark region, and having high brightness at imagebright region.

However, in display device, when light is emitted from light-emittingelement, besides transmitting part of the emitting light through thedisplay panel above, other parts of the emitting light are reflected bythe display panel, or some films under the display panel, back to thebottom of the display device (such as a substrate). Since the bottom ofthe display device will reflect the reflected light again, the actualillumination status above a single light-emitting element, other thanthe central part desired to be illuminating originally, may generatephotoflood at the outer edge. In other words, when observing the displaydevice, a halo may occur surrounding a single light-emitting element.

The edge photoflood (halo) may make it impossible to precisely controlthe bright region and the dark region, leading to deteriorating dynamiccontrast of the image. For example, refer to FIG. 1, a region P1, aregion P2, and a region P3 are adjacent regions. When the region P1 andthe region P3 are desired to be no brightness or low brightness (such asblack), and the middle region P2 is desired to be high brightness (suchas white), the corresponding light-emitting element below the region P2may be lit, while the corresponding light-emitting elements below theregion P1 and the region P3 may be turned off, to perform local dimming.However, when the photoflood is occurred at the light-emitting elementcorresponding to the region P2 below, a light-emitting intensity I ofthe region P2 will be as shown by the plot in FIG. 1, reducing from thecenter to the edge. However, due to the aforementioned photoflood, lightof the region P2 may be partially extended to the supposedly dark regionof the region P1. Therefore, the borders of region A between the regionP1 and the region P2 cannot be clearly distinguished, resulting inblurry borders. In this case, the bright region and the dark regioncannot be clearly distinguished, so dynamic contrast of the image maynot be effectively elevated. In one embodiment, the dynamic contrast canbe obtained by measuring the ratio value of the brightness on geometriccenter of the region P2 (bright region) to the brightness on geometriccenter of the region P1 or the region P3 (dark region), or by measuringthe ratio value of overall brightness of the region P2 to overallbrightness of the region P1 or the region P3. In another embodiment, theappearances of the region P1, the region P2, and the region P3 may beessentially the same or different, while the shape of the region P1,and/or the region P2, and/or the region P3 in FIG. 1 is not limited tosquare, where the shape can also be rectangular, circular, or any otherapplicable shapes, and the present disclosure is not limited hereto. Inone embodiment, the display device may include a plurality of regions(such as P1, P2, and P3 in FIG. 1 and/or other regions), and thus one ofthe regions may also include a plurality of light-emitting elements 103.The plurality of light-emitting elements 103 may emit light of the samecolor, or light of a different color, but the present disclosure is notlimited hereto.

Refer to FIG. 2. According to some embodiments, the present disclosureprovides a display device 10, the display device 10 includes a displaypanel 102 and a light-emitting element 103 disposed under the displaypanel 102, an optical functional film 104 disposed between the displaypanel 102 and the light-emitting element 103, and a diffuser film 105disposed between the display panel 102 and the light-emitting element103. To be more precisely, the diffuser film 105 may be disposed betweenthe optical functional film 104 and the light-emitting element 103. Whenthe light-emitting element 103 emits light, besides transmitting part ofthe emitting light through the display panel 102, another parts of theemitting light may be reflected by the display panel 102, or reflectedby a bottom surface 102A of the display panel 102, back to the bottom ofthe display device 10, such as a top surface 101A of the substrate 101or the region between the diffuser film 105 and the substrate 101. Inone embodiment, when the optical function film 104 is present, since theoptical function film 104 may partially transmit part of the lightreflecting back toward the bottom of the display device 10 (such as topsurface 101A of the substrate 101), or transmit toward at least one sideof the light-emitting element 103, while another part of the reflectedlight may reflect again. Therefore, part of the reflected light mayreflect again before reaching the bottom of the display device 10. Inthe x-direction, a reflection point, such as a reflection point P1, iscloser to the light-emitting element 103 than a reflection point, suchas a reflection point P2, at the bottom of the display device 10. In they-direction, the reflection point P1 is closer to the bottom surface102A of the display panel 102 than the reflection point P2, and thus ahalo size may be reduced. That is, disposing the optical function film104 between the display panel 102 and the light-emitting element 103 mayreduce the halo effect of the display device 10. Furthermore, thereflecting light back toward the substrate 101 may be reduced, therebythe light to be reflected again by the top surface 101A of the substrate101 may be reduced, so that the purpose of reducing the edge photofloodsurrounding the light-emitting element 103 and reducing the halo sizemay be achieved. Additionally, since the diffuser film 105 is disposedbetween the display panel 102 and the light-emitting element 103, thedisplay device 10 may generated substantially uniform light, and theviewing experience may be improved.

Refer to FIG. 2, in the upper part of FIG. 2, a wave W1 is thedistribution of the light intensity I before using the opticalfunctional film 104 and the diffuser film 105, and a wave W2 is thedistribution of the light intensity I after using the optical functionalfilm 104 and the diffuser film 105. By using the optical functional film104 and the diffuser film 105, since the light to be reflected backtoward the substrate 101 is affected by the optical functional film 104,a portion of the light may penetrate the optical functional film 104,and therefore the outer edge light to be reflected by the top surface101A of the substrate 101 is reduced, so the distribution of the lightintensity I above the light-emitting element 103 may be changed from thewave W1 to the wave W2, which means the photoflood beyond the regiondesired to be lit may be further reduced.

The diffuser film 105 described by the present disclosure may be a filmthat may include the effect of diffusing an incident light. In someembodiments, the diffuser film 105 may be a resin film having diffusingparticles distributing in a base material, so the light may betransmitted through mediums with different refractivity, to generaterefraction, reflection, or diffusion phenomena, and the light may beuniformly diffused. In some embodiments, the diffusing particles may beorganic polymers or inorganic materials, such as polymethyl methacrylate(PMMA), silicon dioxide (SiO₂), silicone, or the like, or thecombinations thereof, but the present disclosure is not limited hereto.The materials of the resin film may be polycarbonate (PC), polystyrene,polyester, polyolefin, polyether, polyether-ester, polymethacrylate, orpolyperfluorinated ethylene propylene (PEP), or the like, or thecombinations thereof, but the present disclosure is not limited hereto.

In some embodiments, the haze of the diffuser film 105 may beapproximately greater than 85%; the thickness of the diffuser film 105may range approximately between 0.04 mm and 0.35 mm. By maintaining thehaze and the thickness of the diffuser film 105 within a certain range,the overall thickness of the display device 10 may be reduced, while thedisplay device 10 may still have a certain light source uniformity.Additionally, in some embodiments, a distance between the diffuser film105 and the light-emitting element 103 may be a range approximatelybetween 0 mm and 10 mm to obtain substantial uniformity of the preferredlight source. In some embodiments, the distance described may be theshortest distance between the bottom surface of the diffuser film 105and the light-emitting element 103.

The haze described in the present disclosure may be measured using ahaze meter (NDH-5000SP). The haze may be measured by the followingmethod. After a light ray is transmitted through a measurement target,it will be input to an integration ball. In this procedure, light isseparated by the measurement target into diffused light transmittance(DT) and parallel light transmittance (PT), which are reflected into theintegration ball, followed by being collected by a light receptordevice. The haze may be obtained by measuring collected light rays. Thehaze is defined as the percentage of the diffused light transmittance toa total light transmittance (haze (%)=100×DT/TT), wherein the totallight transmittance (TT) is a sum of the diffused light transmittance(DT) and the parallel light transmittance (PT).

The substrate 101 of the present disclosure may be any suitable, rigidor flexible substrate capable of carrying the light-emitting element103. The materials may include, for example, glass, ceramic (such assilicon nitride or aluminum nitride), sapphire, plastic (such asfiberglass-reinforced plastics (FRP), polyester film, polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), or polyethersulfone(PES) or acrylic resin film) or any other suitable materials forsubstrates.

The light-emitting element 103 described in the present disclosure maybe any suitable light-emitting device. For example, light-emittingdevice may include an electroluminescence (EL) device (such as organicelectroluminescence device or inorganic electroluminescence device), anorganic light-emitting diode (OLED), an inorganic light-emitting diode(LED) (such as micro light-emitting diode, mini light-emitting diode,quantum dot light-emitting diode (QLED)), a laser diode (LD), or thelike, but the present disclosure is not limited hereto.

The display panel 102 described in the present disclosure may be anysuitable non-self-luminous display panel, for example, it may be aliquid-crystal display panel of twisted nematic (TN) mode, in-planeswitching (IPS) mode, fringe field switching (FFS) mode, multi-quadrantvertical alignment (MVA) mode, patterned vertical alignment (PVA) mode,axisymmetric aligned microcell (ASM) mode, optically compensatedbirefringence (OCB) mode, or the like, but the present disclosure is notlimited hereto.

Next, refer to FIG. 3, which illustrates a cross-sectional view of adisplay device 10, according to some embodiments of the presentdisclosure. In some embodiments, the light-emitting element 103 may emitblue light, or the light-emitting element 103 may emit a wavelengthapproximately between 440 nm and 470 nm, or approximately between 440 nmand 550 nm, and the optical functional film 104 may be a blue lighttransmittance film 104 a. Inside the display device 10 (for example,between the display panel 102 and the substrate 101), it may furtherinclude a wavelength transformation layer 106 disposed on the opticalfunction film 104 (or the blue light transmittance film 104 a in thisembodiment) on the side farthest away from the light-emitting element103. In some embodiments, any wavelength in the blue light wavebandemitted from the light-emitting element 103 may be transmitted throughthe blue light transmittance film 104 a, but individual transmittancesof the aforementioned wavelengths to the blue light transmittance film104 a may be approximately the same or different. It should be notedthat when the light intensity of the aforementioned wavelengths are tooweak, the light intensity transmitting through the blue lighttransmittance film 104 a may be too low to be measured by aspectrometer. The spectrometer described herein may be, for example, aCS-2000 or a CS-2000A spectrometer, however, these are merely examples,and are not intended to be limiting.

Refer to FIG. 3. In some embodiments, by choosing a suitable opticalfunctional film 104 to work with a light wavelength emitted from thelight-emitting element 103, the light-emitting element 103 may generatelight transmittance, while reflecting light of other wavebands. In otherwords, as shown in the embodiment of FIG. 3, when the light-emittingelement 103 may emit blue light, and after the wavelength transformationlayer 106 receiving such blue light, the wavelength transformation layer106 will transform this blue light into multi-color light of othercolors (such as white). In this case, the optical functional film 104may be a blue light transmittance film 104 a. In this embodiment, theblue light emitted from the light-emitting element 103 may transmitthrough the blue light transmittance film 104 a to reach the wavelengthtransformation layer 106, and after passing through the wavelengthtransformation layer 106, the emitted blue light will be transformedinto white light. Such white light, after being reflected by, forexample, the display panel 102, may redirect toward the light-emittingelement 103, and may reenter the blue light transmittance film 104 a.Since the blue light transmittance film 104 a may transmit blue light,while reflecting light of other wavebands, therefore only the blue lightpart of the white light entering the blue light transmittance film 104 amay transmit through the blue light transmittance film 104 a to reachthe substrate 101. Other colors of lights within other parts of thewhite light will be reflected, and unable to reach the substrate 101.Therefore, other light colors of the white light (for example, redlight, green light, or red light and green light) may be reflected bythe blue light transmittance film 104 a, before reaching the substrate101. Since the reflection point is closer to the display panel 102, asmaller halo with a color close to yellow (or less obvious than whitelight) may be generated. Furthermore, the light reaching the substrate101 may be reduced, thereby reducing the light to be reflected again bythe substrate 101, which generates the effect of reducing the halo sizeof the light-emitting element 103.

Similarly, in some embodiments, if the light-emitting element 103emitted blue and red light, then the optical function film 104 may beblue light and red light transmittance film, and the wavelengthtransformation layer 106 may be a layer that transforms blue light orred light into white light. Blue light and red light transmittance filmmay allow blue light and red light, which is directed toward thelight-emitting element 103 after reflecting, to transmit, whilereflecting light in other wavebands, in order to reduce the lightreaching the substrate 101, thereby achieving the effect of reducing thehalo size.

Materials of the blue light transmittance film 104 a described in thepresent disclosure are not specifically limited, as long as they aresuitable materials (which the film is made of) that allow the desiredblue light wavelength to transmit. For example, they may be polyethylenenaphthalate (PEN), polycarbonate (PC), polyethylene terephthalate (PET),or the like, but the present disclosure is not limited hereto. The bluelight transmittance film 104 a may be a stack of multiple layers, but itmay also be a single layer. In some embodiments, the blue lighttransmittance film 104 a may have at least, or in average, approximatelygreater than 50% transmittance at wavelengths within an approximaterange of 380 nm to 550 nm, or 440 nm to 550 nm. In some embodiments, ina visible region outside wavelengths of an approximate range of 550 nmto 700 nm, the blue light transmittance film 104 a may have at least, orin average, approximately greater than 90% reflectivity, or greater than95% reflectivity. The reflectivity described in the present disclosuremay be measured by any suitable equipment, for example, may be measuredby High-Performance Desktop Colorimeter (model: ColorQuest XE, lightsource spectrum range: 400 nm-700 nm), but the present disclosure is notlimited hereto.

Refer to FIG. 3. The locations of layers within the display device arenot specifically limited, as long as the wavelength transformation layer106 is disposed on the side of the blue light transmittance film 104 athat is farthest away from the light-emitting element 103. In someembodiments, in order for the blue light passing through the blue lighttransmittance film 104 a to be transformed more effectively, thewavelength transformation layer 106 and the blue light transmittancefilm 104 a may directly contact each other, or there are no other layersbetween the wavelength transformation layer 106 and the blue lighttransmittance film 104 a. In addition, in some embodiments, the diffuserfilm 105 may be disposed between the blue light transmittance film 104 aand the light-emitting element 103, compared to disposing the diffuserfilm 105 between the blue light transmittance film 104 a and thewavelength transformation layer 106, since the light emitted from thelight-emitting element 103 may be collimated before passing through theblue light transmittance film 104 a, the display device overall may havemore excellent brightness. The thickness of the blue light transmittancefilm 104 a is also not specifically limited. In some embodiments, inconsideration of support strength, the thickness of the blue lighttransmittance film 104 a is within an approximate range of 0.03 mm to0.50 mm. In some embodiments, for increasing the effect and completenessof reflection, the optical functional film 104 (for example, the bluelight transmittance film 104 a of FIG. 3) may be a continuous film: Thatis, a layer covering almost the entire display panel 102. In someembodiments, there may be a distance D_(f1) between the blue lighttransmittance film 104 a and the light-emitting element 103, and thedistance D_(f1) may be a range between 0 mm and 10 mm. In someembodiments, the distance D_(f1) described above may be the shortestdistance between the bottom surface 104 a-A of the blue lighttransmittance film 104 a and the light-emitting element 103.

The wavelength transformation layer 106 described in the presentdisclosure, in order to have layers of wavelength transformationmaterials, may transform wavelength of the received light into lightwith different wavelength, which is then emitted. For example, after thewavelength transformation layer 106 receives blue light, white light isthen emitted. The wavelength transformation layer 106 is notspecifically limited. For example, it may be quantum dot film (QDF) orphosphor film, such as resin films includes quantum dot materials orincludes phosphor powder materials. The resin described may betransparent resin, for example, epoxy resin, polyimide resin, acrylicresin, silicone resin, or the combinations thereof, but the presentdisclosure is not limited hereto. By selecting suitable inorganicphotoluminescence materials, organic photoluminescence materials, orquantum dot materials, after the wavelength transformation layer 106receives light emitted from the light-emitting element 103, maytransform into multi-color light (which may still have the lightwaveband emitted from the light-emitting element 103, or may not havethe light waveband emitted from the light-emitting element 103)comprising other colors (different wavelength).

For example, quantum dot materials may be binary mixtures, ternarymixtures, or quaternary mixtures of II-VI group, III-V group, IV-VIgroup, or IV group. For example, quantum dot materials of binarymixtures may be CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe (II-VIgroup), AN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb(III-V group), PbS, PbSe, PbTe, SnS, SnSe, SnTe (IV-VI group), SiC, SiGe(IV group), or the like, or the combinations thereof. For example,quantum dot materials of ternary mixtures may be CdSeS, CdSeTe, CdSTe,ZnSeS, ZnTeSe, ZnSeTe, ZnSTe, CdZnS, CdZnSe, CdZnTe (II-VI group), GaNP,GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AINAs, AlNSb, AlPAs, AlPSb (III-Vgroup), or the like, or the combinations thereof. For example, quantumdot materials of quaternary mixtures may be CdZnSeS, CdZnSeTe, HgZnTeS(II-VI group), GaAlNAs, GaAlNSb, GaInNP, InAlNP (III-V group), SnPbSSe,SnPbSeTe, SnPbSTe (IV-VI group), or the like, or the combinationsthereof. Quantum dot materials may also be selected from IV groupmaterials, such as Si, Ge, or the combinations thereof.

For example, phosphor powder materials may be Y₃Al₅O₁₂, Gd₃Ga₅O₁₂:Ce,(Lu, Y)₃Al₅O₁₂:Ce, SrS:Eu, SrGa₂S₄:Eu, (Sr, Ca, Ba)(Al, Ga)₂S₄:Eu, (Ca,Sr)S:(Eu, Mn), (Ca, Sr)S:Ce, (Sr, Ba, Ca)₂Si₅N₈:Eu, (Sr, Ba, Ca)(Al,Ga)SiN₃:Eu, (Ba, Sr, Ca)₂SiO₄:Eu, (Ca, Sr, Ba)SW₂O₂N₂:Eu, or CdZnSe, butthe present disclosure is not limited hereto.

Next, refer to FIG. 4. In some embodiments, there may be a reflectivelayer 107 disposed between the light-emitting element 103 and thesubstrate 101. The materials of the reflective layer 107 are notspecifically limited, as long as they are layers that can reflect light.In some embodiments, the reflective layer 107 may be a white ink with athickness in an approximate range of 0.05 mm to 0.35 mm, or ametal-containing layer with a thickness in an approximate range of 0.05mm to 0.35 mm. In some embodiments, the reflective layer 107 may be acontinuous layer, and may approximately cover an upper surface of thesubstrate 101 to increase the light source usage from the light-emittingelement 103. Yet in some embodiments, a reflectivity of the reflectivelayer 107 may be approximately greater than 95%, when the reflectivityof the reflective layer 107 is between 80% and 95%, or approximatelygreater than 80%, the halo size may all be reduced. In some embodiments,by coating, for example, photoresist of a specific color or using awhite resin with a specific coating/screen printing on the surface ofthe reflective layer 107 away from the substrate 101, the reflectivelayer 107 cooperates with the optical functional film 104 to reflect theoptical light that can be transmitted by the functional film 104. Forexample, when the optical functional film 104 is the blue lighttransmittance film 104 a, the reflective layer 107 may be the reflectivelayer 107 reflecting the blue light waveband, and may further reduce thelight to be reflected again through the reflective layer 107.

Refer to FIG. 5, which illustrates a cross-sectional view of a displaydevice 10, according to other embodiments of the present disclosure. Insome embodiments, the light-emitting elements 103 may also be alight-emitting element that emits white light. In this case, aspreviously described, a transflective film 104 b, as the opticalfunctional film 104, may be used to cooperate with the light wavebandemitted from the light-emitting element 103. In some embodiments, thetransflective film 104 b may partially transmit and partially reflectall visible light waveband. Therefore, when the light-emitting element103 emits white light, the transflective film 104 b disposed above thelight-emitting element 103 may similarly reflect part of the lighttoward the side of the light-emitting element 103 before arriving thesubstrate 101, and therefore, part of the light may be reflected beforereaching the substrate 101, to reduce the amount of light reaching thesubstrate 101, thereby reducing the size of the halo generated by thelight-emitting element 103.

In some embodiments, the transflective film 104 b may reflect andtransmit the entry light, and the transflective film 104 b may not altera polarization condition of the entry light. The thickness and materialsof the transflective 104 b are not specifically limited, as long as avisible light waveband may partially transmit and partially reflect. Insome embodiments, the transflective film 104 b may be metal-containinglayer with a thickness in an approximate range of 0.03 mm to 0.40 mm.For example, it may be the transflective film 104 b of Ag-containingalloy. In some embodiments, the transflective film 104 b may be a singlelayer or a multiple-layer structure. In some embodiments, a minimumreflectivity of the transflective film 104 b, at wavelengths within arange of 380 nm and 700 nm, is approximately greater than 50%.

Furthermore, even though in the embodiment shown in FIG. 5, the diffuserfilm 105 is disposed between the transflective film 104 b and thelight-emitting element 103, in some embodiments, the transflective film104 b may also be disposed between the diffuser film 105 and thelight-emitting element 103. In some embodiments, there may be a distanceD_(f2) between the transflective film 104 b and the light-emittingelement 103, the distance D_(f2) may be between 0.1 mm and 10.0 mm. Insome embodiments, the distance D_(f2) described may be the shortestdistance between a bottom surface 104 b-A of the transflective film 104b and the light-emitting element 103.

Also, refer to FIG. 6. In some embodiments, as previously described,when the optical functional film 104 is the transflective film 104 b,the display device 10 may further include the reflective layer 107disposed between the light-emitting element 103 and the substrate 101.The reflective layer 107 used herein may be the same as theaforementioned reflective layer 107, thus it is not repeated herein. Insome embodiments, a reflective index of the reflective layer 107 mayrange from 0.80 to 0.95.

Next, refer to FIG. 7. FIG. 7 illustrates a cross-sectional view of adisplay device 10, according to some embodiments of the presentdisclosure. In some embodiments, when the diffuser film 105 of thedisplay device 10 is disposed between the optical functional film 104and the light-emitting elements 103, the diffuser film 105 may havemicro-structures 105 m on a side of the diffuser film 105 that may benear the light-emitting elements 103, for example, a surface 105A of thediffuser film 105. The micro-structures 105 m may have recesses 108, andthe recesses 180 may be directed toward the light-emitting elements 103,respectively (for example, recesses 108 may be disposed along negativeY-direction). Refer to FIG. 8, the recesses 108 may contact, forexample, the substrate 101 or the reflective layer (not show) which maybe disposed between the light-emitting elements 103 and the substrate101, so cavities 109 may be formed between the recesses 108 and thesubstrate 101 or the reflective layer. In some embodiments, the cavities109 may accommodate one or more light-emitting elements 103. The lightoutput condition of the light-emitting elements 103, which may beaccommodated by the micro-structures 105 m, may be further controlled,to change the halo size of the light-emitting elements 103, therebymodifying the visual effect of the display device 10.

In some embodiments, a haze of the micro-structures 105 m and the hazeof the diffuser film 105 may be different. For example, the haze of themicro-structures 105 m may be greater than, or less than the haze of thediffuser film 105. The transmittance of the micro-structures 105 m andthe transmittance of the diffuser film 105 in the same waveband may alsobe different. For example, the transmittance of the micro-structures 105m may be greater than, or less than the transmittance of the diffuserfilm 105.

The micro-structures 105 m and the diffuser film 105 may include thesame materials, but they may also use different materials. The materialsused by micro-structures 105 m are also not specifically limited. In oneembodiment, the materials of the micro-structures 105 m may be polymers,such as ultra violet acrylic resin, polymethyl methacrylate,polycarbonate, silica gel, polyethylene terephthalate (PET), or thelike, or may also be the combinations thereof, but the presentdisclosure is not limited hereto. When the micro-structures 105 m andthe diffuser film 105 use the same materials, the micro-structures 105 mand the diffuser film 105 may also be formed in the same process. Forexample, in some embodiments, the diffuser film 105 and themicro-structures 105 m may be simultaneously formed by the desired shapemold of the micro-structures 105 m, through injection molding andknockout methods.

Refer to FIG. 8, in some embodiments, the cross-sections of the recesses108 of the micro-structures 105 m (or the shape of the cavities 109formed between the recesses 108 and the substrate 101 or the reflectivelayer) may be a triangle, an arch, a trapezoid, or the like, but thepresent disclosure is not limited hereto. The micro-structures 105 m mayhave recesses 108 with different sizes and/or shapes, but the height ofeach micro-structure 105 m may be the same or different.

By setting specific shapes on the recesses 108 of the micro-structures105 m, the light-emitting elements 103 may have different dimmingeffects. For example, refer to FIG. 8, FIG. 8 illustratescross-sectional views of individual micro-structures 105 m, according tosome embodiments of the present disclosure, while the structures abovethe diffuser film 105 are omitted. As shown on the leftmost view of FIG.8, a shape of the recess 108 of the micro-structure 105 m may be atriangle, for example, may be isosceles triangle. By embodying thelight-emitting element 103 within the recess 108, an angle of outputlight generated by the light-emitting element 103 may be increased byrefraction, to elevate the light uniformity source, or may reduce thenumber of light-emitting element 103 used in an unit area.

In some embodiments, as shown on the middle and the rightmost views ofFIG. 8, cross-sections of the recesses 108 of the micro-structures 105 mmay be a trapezoid or an arch. By disposing the light-emitting elements103 within the recesses 108 of the arch or the trapezoid, the angle ofoutput light generated by the light-emitting element 103 may be furtherreduced, to elevate the dynamic contrast of the display device image.

In the display device described in the present disclosure, there maycontain other layers according to actual demand. For example, in someembodiments, there may have other films between the optical functionalfilm 104 and the display panel 102 in the display device. For example,there may be prism lens (or may be referred to brightness enhancementfilm (BEF) or dual brightness enhancement film (DBEF)) under the displaypanel 102, to redirect off-axis light and increase on-axis light passingthrough the display panel 102, and to elevate image brightness viewed byobservers.

By introducing a blue light transmittance film as an optical functionalfilm and the diffuser film between the blue light light-emitting elementand the wavelength transformation layer, since the light reflected backtoward the substrate and the reflective layer may be reduced, andtherefore the size of the halo generated by the light-emitting elementmay be effectively reduced. For example, the diameter of the halo may bereduced by 50%. In some embodiments, the halo size may be measured bylighting one or more light-emitting elements of the aforementioneddisplay device, measuring the brightness of the one or morelight-emitting elements. The brightest part of the center is set to 100%brightness, and the radius of the halo is a distance from the 100%brightness point to a 5% brightness point, so the halo size is twice thesize of the aforementioned radius.

Although several embodiments and their advantages of the presentdisclosure have been disclosed above, it should be understood that anyof those skilled in the art may make changes, replacements, andretouches without departing from the spirit and scope of the disclosure.Furthermore, the scope of the present disclosure is not intended to belimited by the process, equipment, manufacture, material composition,device, method, and procedure of the specific embodiments described inthe specification, any of those skilled in the art may understand fromthe present disclosure, the present or future process, equipment,manufacture, material composition, device, method, and procedure to bedeveloped, as long as the embodiment described herein may be carried outwith approximately similar function or be obtained with approximatelysimilar result, may all be applied according to the present disclosure.Therefore, the scope of the present disclosure includes theaforementioned process, equipment, manufacture, material composition,device, method, and procedure. Additionally, based on the multipleimplementation forms mentioned previously, those skilled in the artshould be able to understand, the present disclosure has manyimplementation methods. Every claim may also construct into anindividual embodiment, and the scope of the present disclosure alsoincludes various claims and combinations of the embodiments. The scopeof the present disclosure should be based on the scope of the claimslisted below.

What is claimed is:
 1. A display device, comprising: a display panel; alight-emitting element disposed under the display panel; an opticalfunctional film disposed between the display panel and thelight-emitting element, wherein the optical functional film is capableof transmitting at least part of light emitted from the light-emittingelement; and a diffuser film disposed between the display panel and thelight-emitting element, wherein a haze of the diffuser film is greaterthan 85%, and a thickness of the diffuser film ranges from 0.1 mm to 0.3mm.
 2. The display device of claim 1, further comprising a substrate,wherein the light-emitting element is disposed on the substrate.
 3. Thedisplay device of claim 1, wherein the display panel has a brightregion, and the bright region corresponds to the light-emitting element.4. The display device of claim 1, wherein the diffuser film is disposedbetween the optical functional film and the light-emitting element. 5.The display device of claim 4, wherein a distance between the diffuserfilm and the light-emitting element is between 0 mm and 10 mm.
 6. Thedisplay device of claim 1, wherein the light-emitting element emits bluelight, and the optical functional film is a blue light transmittancefilm.
 7. The display device of claim 6, wherein the display devicefurther comprises a wavelength transformation layer, disposed on a sideof the blue light transmittance film away from the light-emittingelement.
 8. The display device of claim 6, wherein a distance between abottom surface of the blue light transmittance film and thelight-emitting element is between 0 mm and 10 mm.
 9. The display deviceof claim 6, further comprising a reflective layer 107 disposed betweenthe light-emitting element 103 and the substrate
 101. 10. The displaydevice of claim 1, wherein the optical functional film is atransflective film.
 11. The display device of claim 10, wherein thetransflective film is a multi-layer structure.
 12. The display device ofclaim 10, wherein a distance between a bottom surface of thetransflective film and the light-emitting element is between 0.1 mm and10.0 mm.
 13. The display device of claim 1, wherein the light-emittingelement emits white light, wherein the optical functional film isdisposed between the diffuser film and the light-emitting element. 14.The display device of claim 9, wherein a reflective index of thereflective layer ranges from 0.80 to 0.95.
 15. The display device ofclaim 1, wherein a side of the diffuser film close to the light-emittingelement has a micro-structure, the micro-structure has a recess facingthe light-emitting element.
 16. The display device of claim 15, whereinthe haze of the diffuser film is different from a haze of themicro-structure.
 17. The display device of claim 15, wherein themicro-structure contacts the substrate.
 18. The display device of claim15, further comprises a cavity between the recess and the substrate. 19.The display device of claim 15, wherein a shape of the recess in across-section view is a triangle, an arch, or a trapezoid.
 20. Thedisplay device of claim 18, wherein the cavity comprises one or morelight-emitting elements.